OTTO, RUDOLPH° (1869–1937), German Protestant theologian and historian of religion. Otto's major contribution to the study of comparative religion was his emphasis on, and analysis of, the notion of the "holy" as the specific and characteristic feature of religious experience. The "holy" is not identical with the true, the beautiful, or the moral. It is "awesome" in its grandeur and mysterious majesty. It is "wholly other" and causes ambivalent reactions, inspiring love as well as fear and producing confidence and joy as well as trembling. To express the range of meaning of the idea of the holy, Otto coined the term "numinous" (from Lat. Numen, "divine power"). While Otto's analysis may not apply to all religions, it well describes the religious consciousness of biblical religion and the religions influenced by it. The various aspects of the numinous as described by Otto correspond to the complementary categories of "love of God" and "fear of God" in Jewish thought, and more especially to the feelings evoked and emphasized by the liturgy of Rosh Hashanah and the Day of Atonement (the "Days of Awe"). In fact, Otto illustrated his argument by quoting not only from the Bible but also from the piyyutim in the prayer book for the High Holidays. Among Otto's important works are West-oestliche Mystik (1926; Mysticism, East and West, 1932) and Reich Gottes und Menschensohn (1934; The Kingdom of God and the Son of Man, 1938), but his best-known work is Das Heilige (1917; The Idea of the Holy, 1923).
M.J.H.M. Poorthuis, in: Purity and Holiness (2000), 107–27; J.A. Levisohn, in: Journal of Jewish Education, 70:1–2 (2004), 4–21.